This invention relates to a one-part moisture curable composition which exhibits excellent storage stability as well as room temperature-curable good adhesion and excellent sheet property in rubber elasticity and strength.
Organic polymers having a reactive silyl group, namely, modified silicone resins have become a versatile resin for use as a sealant having well balanced properties in coating and sealing applications since such polymers are room temperature-curable and the cured products thereof exhibit rubber elasticity owing to their polyether backbone and the like.
However, modified silicone resin has low strength inherently, therefore, modified silicone resin with excellent strength is desired.
In view of such situation, various curable compositions comprising a curable compound capable of imparting the modified silicone resin with strength have been proposed. Examples of such compound are epoxy compounds and isocyanate compounds.
However, when a one-part composition is produced from a modified silicone resin and an isocyanate compound, the isocyanate compound suffers from curing failure due to the blocking of the isocyanate group by the alcohol generated in the curing of the modified silicone resin. When an amine or the like is used for the curing agent of the isocyanate compound, and the isocyanate compound and the amine are stored as a mixture, the mixture undergoes gelation, curing, and the like during its storage and the mixture was not at all storage stable. Even if a latent curing agent having the amine blocked were used, the mixture still suffered from insufficient storage stability.